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美好的一天!使用EL將JSP數據轉換爲Servlet
我想刪除一條記錄。但在此之前我刪除它,我將展示使用JSP的確認消息如下:(摘自「ID」 Servlet的ID和姓名)
<form action = "Delete">
Id: ${student.id} <br>
<input type="submit" value="Delete">
</form>
而且我刪除代碼如下:
public class Delete extends HttpServlet {
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html;charset=UTF-8");
PrintWriter out = response.getWriter();
String query = "Delete FROM customer WHERE id = ?";
try {
Context context = new InitialContext();
DataSource ds = (DataSource) context.lookup("jdbc/myDatasource");
Connection con = ds.getConnection();
PreparedStatement stmt = con.prepareStatement(query);
int id = Integer.parseInt(request.getParameter("id")); //ERROR HERE?
stmt.setInt(1, id);
stmt.executeUpdate(query);
} catch (Exception ex) {
out.println("Error.... " + ex);
}
}
但我有一個null pointer exeption
。看起來這個ID不能被讀取。 (但我不確定)。如何使用EL將數據從JSP傳遞給Servlet?導致錯誤的原因是什麼?如何解決?謝謝。
啊好的:)你在回答這麼快。謝謝。 – newbie 2011-03-07 17:31:45